Cleanrooms and equipment

Which type of cleanroom blows clean air from parts of the ceiling and maintains cleanliness by mixing with and diluting the room air? Its cleanliness is lower than with unidirectional flow, but its equipment cost is lower.

  1. ANon-unidirectional (turbulent) flow
  2. BDownflow (vertical unidirectional flow)
  3. CMini-environment
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Answer: A. Non-unidirectional (turbulent) flow

Non-unidirectional flow supplies clean air through ceiling diffusers and exhausts it while mixing with room air to dilute particles. It needs less airflow and costs less to build and run, but the cleanliness it can reach is lower than with unidirectional flow, so it is used for areas of around ISO Class 6 to 8.

  • A. Correct. It works by mixing and diluting air.
  • B. Downflow sends air in one direction from the whole ceiling to the floor.
  • C. A mini-environment cleans only the small space around the wafers.
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More Cleanrooms and equipment questions

  1. Which filter is used to remove airborne molecular contamination (AMC) such as ammonia and organics from cleanroom air?
  2. In cleanroom air conditioning, which unit filters outside air and adjusts its temperature and humidity before supplying it to the recirculating room air?
  3. In a fab's automated material handling system, which automated storage holds FOUPs temporarily until their next process step?
  4. In automated transport in a bay-type fab, which pair correctly names transport between bays and transport linking tools within a bay?
  5. Which cleanroom style places tools in a large room with few partitions, ensuring wafer cleanliness with sealed carriers such as FOUPs and mini-environments?